CHANGES FROM 3.6a TO 3.6b

* Remove images from the correct list when they are removed while in the
  alternate screen (reported by xlabai at tencent dot com).

CHANGES FROM 3.6 TO 3.6a

* Fix a buffer overread and an infinite loop in format processing (reported by
  Giorgi Kobakhia, issue 4735).

* Allow drag in alternate screen again (issue 4743 reported by Brad King).

* Fix y offset of mouse if status at top (issue 4738 from Michael Grant).

* Add a missing skin tone (from Jake Stewart, issue 4736).

* Allow characters to be combined in either order (issue 4726, reported by Jake
  Stewart).

* Fix horizontal mouse resizing when pane status lines are on (from Michael
  Grant, issue 4720).

* Fix noattr so it does not delete attributes set in the style itself (issue
  4713).

* Newer libevents do not allow event_del on a zero'd event (issue 4706).

* Place cursor on correct line if message-line is not 0 (issue 4707).

* Fix compile error on FreeBSD (from Yasuhiro Kimura, issue 4701).

CHANGES FROM 3.5a TO 3.6

* Add seconds options for clock mode (issue 4697).

* Add a resize callback for menus so that they are correctly moved on resize
  (issue 4696).

* Make -v to source-file pass through to subsequent source-file commands (issue
  4216).

* If display-popup is used inside a popup, modify that popup (issue 4678).

* Add selection-mode command to expilcitly set the selection mode in copy mode
  (issue 3842).

* Save and restore images in alternate screen (issue 3732).

* Ignore Hangul filler character (issue 3998).

* Improve handling of regional indicators and emoji modifiers (issue 3998).

* Preserve marked pane with swap-window and move-window (issue 3443).

* Set and check COLORTERM as a hint for RGB colour.

* If tmux receives a palette request (OSC 4) in a pane and the palette entry
  has not been set, send a request to the most recently used client and
  forward any response instead (based on change from Tim Culverhouse, issue
  4665).

* Add -l flag to command-prompt to disable splitting into multiple prompts
  (issue 4483).

* Don't enter copy mode on mouse wheel in alternate screen (issue 3705).

* Add commands to centre the cursor in copy mode (issue 4662).

* Support case insensitive search in modes in the same way as copy mode
  (like emacs, so all-lowercase means case insensitive) (issue 4396).

* Fix the logic of the no-detached case for the detach-on-destroy option (from
  Martin Louazel, issue 4649).

* Add buffer_full format variable (from Mohammad AlSaleh, issue 4630).

* Introduce a new window option, tiled-layout-max-columns, which configures the
  maximum number of columns in the tiled layout.

* Add support for DECRQSS SP q (report cursor style), DECRQM ?12 (report cursor
  blink state) and DECRQM ?2004, ?1004, ?1006 (report mouse state) ( rom
  Andrea Alberti, issue 4618).

* Fix missing argument from OSC 4 reply (issue 4596).

* Add -k flag to display-popup which allows any key to dismiss the popup once
  the command has exited (from Meriel Luna Mittelbach, issue 4612).

* Add nicer default second and third status lines (from Michael Grant, issue
  4490).

* Add a pane-border-lines "spaces" value to use spaces for pane borders (issue
  4587).

* Replace invalid UTF-8 characters with the placeholder instead of ignoring
  them (issue 4514).

* Fix incorrect handling of Korean Hangul Jamo characters (from Roy Jung, issue
  4546).

* Allow uppercase letters in gray/grey color names (from Pavel Roskin, issue
  4560).

* Add sorting to W, P, L loop operators (from Michael Grant, issue 4516).

* Detect support for OSC 52 using the device attributes report (from James
  Holderness, issue 4539).

* Add noattr for styles and use in mode-style to allow whether attributes are
  ignored or used to be configured (issue 4498).

* Add a set-default style attribute which replaces the current default colours
  and attributes completely.

* Add -E to run-shell to forward stderr as well as stdout (issue 4246).

* Add an option variation-selector-always-wide to instruct tmux not to
  always interpret VS16 as a wide character and assume the terminal does
  likewise.

* Switch to getopt_long from OpenSSH (from Koichi Murase, issue 4492).

* Add more features for boolean expressions in formats: 1) extend && and || to
  support arbitrarily many arguments and 2) add ! and !! for not and not-not
  (from David Mandelberg).

* Do not mistake other DCS sequences for SIXEL sequences (from James
  Holderness, issue 4488).

* Improve #? conditional expression in formats: add support for else if and
  default empty string if no else value (from David Mandelberg, issue 4451).

* Add default-client-command to set the command used if tmux is run without a
  command; the default stays new-session (from David Mandelberg, issue
  4422).

* Add S-Up and S-Down to move windows in tree mode (from David Mandelberg,
  issue 4415).

* Add mode 2031 support to automatically report dark or light theme. tmux will
  guess the theme from the background colour on terminals which do not
  themselves support the escape sequence (from Jonathan Slenders, issue 4353).

* Add -M flag to capture-pane to use the copy mode screen (issue 4358).

* Align index numbers in trees (from David Mandelberg, issue 4360).

* Add display-message -C flag to update pane while message is displayed (from
  Vitaly Ostrosablin, issue 4363).

* Make list-commands command show only one command if an argument is given
  (from Ilya Grigoriev, issue 4352).

* Count line numbers correctly inside strings in configuration files (reported
  by Pedro Navarro, issue 4325).

* Map bright black (colour 8) to white (7) if the background is black on
  terminals with only eight colours so the text is not invisible (from Dmytro
  Bagrii, issue 4322).

* New codepoint-widths option allowing users to override the width of
  individual Unicode codepoints.

* Add a nesting limit to source-file (from Fadi Afani, issue 4223).

* Add copy-mode-position-style and copy-mode-selection-style options for copy
  mode.

* Add no-detach-on-destroy client option (issue 4242).

* Add input-buffer-size option (from Ken Lau).

* Add support for a scrollbar at the side of each pane. New options
  pane-scrollbars turn them on or off, pane-scrollbars-position sets the
  position (left or right), and pane-scrollbars-style to set the colours (from
  Michael Grant, issue 4221).

* Allow control characters to be entered at the command prompt by prefixing
  with C-v (from Alexander Arch, issue 4206).

* Do not attempt to search for zero length strings (from Alexander Arch, issue
  4209).

* Preserve tabs for copying and capture-pane (from Alexander Arch, issue
  4201).

* Increase the maximum for repeat-time.

* Adjust how Ctrl and Meta keys are sent to use standard representation if
  available in mode 1 (from Stanislav Kljuhhin, issue 4188).

* Allow attributes in menu style (from Japin Li, issue 4194).

* Add a sixel_support format variable which is 1 if SIXEL is supported, always
  0 on OpenBSD (requested by Misaki Masa, issue 4177).

* Add prompt-cursor-colour and prompt-cursor-style to set the style of the
  cursor in the command prompt and remove the emulated cursor (from Alexander
  Arch, issue 4170).

* Add initial-repeat-time option to allow the first repeat time to be increased
  and later reduced (from David le Blanc, issue 4164).

* Send focus events to pane when entering or leaving popup (issue 3991).

* Add copy-mode-position-format to configure the position indicator.

* Add -y flag to disable confirmation prompts in modes (issue 4152).

* Add -C and -P flags to the copy commands in copy mode: -C prevents the
  commands from sending the text to the clipboard and -P prevents them from
  adding the text as a paste buffer (issue 4153).

* Preserve transparency and raster attribute dimensions when sending a SIXEL
  image, and avoid collapsing empty lines (issue 4149).

* Bypass permission check for Cygwin (based on a change by Yuya Adachi via
  Rafael Kitover, issue 4148).

* Add MSYSTEM to default update-environment (for Cgywin).

* Set client stdout file descriptor also for Cgywin (from Michael Wild via Rafael
  Kitover, issue 4148).

* Use global cursor style and colour options for modes instead of default
  (issue 4117).

* Fix pasting so it does not interpret keys but instead copies the input
  without interpretation (reported by Mark Kelly).

* Try to query window pixel size from the outside terminal if the values
  returned by TIOCGWINSZ are zero (Dmitry Galchinsky, issue 4099).

CHANGES FROM 3.5 TO 3.5a

* Do not translate BSpace as Unicode with extended keys.

* Fix so that keys with Shift are represented correctly with extended keys.

* Revert to using /bin/sh for #() and run-shell and if-shell; the change to use
  default-shell only applies now to popups.

* Fix grey colour without a number suffix in styles.
 
CHANGES FROM 3.4 TO 3.5

* Revamp extended keys support to more closely match xterm and support mode 2
  as well as mode 1. This is a substantial change to key handling which changes
  tmux to always request mode 2 from parent terminal, changes to an unambiguous
  internal representation of keys, and adds an option (extended-keys-format) to
  control the format similar to the xterm(1) formatOtherKeys resource.

* Clear an overlay (popup or menu) when command prompt is entered.

* Add copy-mode -d flag to scroll a page down if in copy mode already (matching
  -e).

* Display hyperlinks in copy mode and add copy_cursor_hyperlink format to get
  the hyperlink under the cursor.

* Add a prefix timeout option.

* Mouse move keys are not useful as key bindings because we do not turn them on
  unless the application requests them. Ignore them so they do not cause the
  prefix to be canceled

* Add search_count and search_count_partial formats in copy mode.

* Do not reset mouse pane if clicked on status line,

* Add mirrored versions of the main-horizontal and main-vertical layouts where
  the main pane is bottom or right instead of top or left.

* Allow REP to work with Unicode characters.

* Fix size calculation of terminators for clipboard escape sequences.

* Treat CRLF as LF in config files where it is easy to do so.

* The Linux console has some bugs with bright colours, so add some workarounds
  for it.

* If built with systemd, remove some environment variables it uses.

* Adjust the logic when deleting last buffer to better preserve the selection:
  if selecting the element below the deleted one fails (because as the last
  one), select the one above it instead.

* Add --enable-jemalloc to build with jemalloc memory allocator (since glibc
  malloc is so poor).

* Add a way (refresh-client -r) for control mode clients to provide OSC 10 and
  11 responses to tmux so they can set the default foreground and background
  colours.

* Add N to search backwards in tree modes.

* Use default-shell for command prompt, #() and popups.

* Revert part of a change intended to improve search performance by skipping
  parts of lines already searched, but which in fact skipped the ends of lines
  altogether.

* Add a command-error hook when a command fails.

* Add an option allow-set-title to forbid applications from changing the pane
  title.

* Correct handling of mouse up events (don't ignore all but the last released
  button), and always process down event for double click.

* Fix a crash if focusing a pane that is exiting.

* Pick newest session (as documented) when looking for next session for
  detach-on-destroy.

* Reduce default escape-time to 10 milliseconds.

* Add display-menu -M to always turn mouse on in a menu.

* Look for feature code 21 for DECSLRM and 28 for DECFRA in the device
  attributes and also accept level 1.

* Fix crash if built with SIXEL and the SIXEL colour register is invalid; also
  remove SIXEL images before reflow.

* Do not notify window-layout-changed if the window is about to be destroyed.

* Do not consider a selection present if it is empty for the selection_active
  and selection_present format variables.

* Fix split-window -p.

CHANGES FROM 3.3a TO 3.4

* Add options keep-last and keep-group to destroy-unattached to keep the last
  session whether in a group.

* Don't allow paste-buffer into dead panes.

* Add -t to source-file.

* Rewrite combined character handling to be more consistent and to support
  newer Unicode combined characters.

* Add basic support for SIXEL if built with --enable-sixel.

* Add a session, pane and user mouse range types for the status line and add
  format variables for mouse_status_line and mouse_status_range so they can be
  associated with different commands in the key bindings.

* Add flag (-o) to next-prompt/previous-prompt to go to OSC 133 command output.

* Add options and flags for menu styles (menu-style, menu-border-style) similar
  to those existing for popups.

* Add support for marking lines with a shell prompt based on the OSC 133 extension.

* Check for libterminfo for NetBSD.

* Add "us" to styles for underscore colour.

* Add flags (-c and -y) to change the confirm key and default behaviour of
  confirm-before.

* Use ncurses' new tparm_s function (added in 6.4-20230424) instead of tparm so
  it does not object to string arguments in c apabilities it doesn't already
  know. Also ignore errors from tparm if using previous ncurses versions.

* Set default lock command to vlock on Linux if present at build time.

* Discard mouse sequences that have the right form but actually are invalid.

* Add support for spawning panes in separate cgroups with systemd and a
  configure flag (--disable-cgroups) to turn off.

* Add a format (pane_unseen_changes) to show if there are unseen changes while
  in a mode.

* Remove old buffer when renaming rather than complaining.

* Add an L modifier like P, W, S to loop over clients.

* Add -f to list-clients like the other list commands.

* Extend display-message to work for control clients.

* Add a flag to display-menu to select the manu item selected when the menu is
  open.

* Have tmux recognise pasted text wrapped in bracket paste sequences, rather
  than only forwarding them to the program inside.

* Have client return 1 if process is interrupted to an input pane.

* Query the client terminal for foreground and background colours and if OSC 10
  or 11 is received but no colour has been set inside tmux, return the colour
  from the first attached client.

* Add send-keys -K to handle keys directly as if typed (so look up in key
  table).

* Process escape sequences in show-buffer.

* Add a -l flag to display-message to disable format expansion.

* Add paste-buffer-deleted notification and fix name of paste-buffer-changed.

* Do not attempt to connect to the socket as a client if systemd is active.

* Add scroll-top and scroll-bottom commands to scroll so cursor is at top or
  bottom.

* Add a -T flag to capture-pane to stop at the last used cell instead of the
  full width. Restore the previous behaviour by making it default to off unless
  -J is used.

* Add message-line option to control where message and prompt go.

* Notification when a paste buffer is deleted.

* Add a Nobr terminfo(5) capability to tell tmux the terminal does not use bright
  colours for bold.

* Change g and G to go to top and bottom in menus.

* Add a third state "all" to allow-passthrough to work even in invisible panes.

* Add support for OSC 8 hyperlinks.

* Store the time lines are scrolled into history and display in copy mode.

* Add a %config-error reply to control mode for configuration file errors since
  reporting them in view mode is useless.

* A new feature flag (ignorefkeys) to ignore terminfo(5) function key
  definitions for rxvt.

* Pass through first argument to OSC 52 (which clipboards to set) if the
  application provides it.

* Expand arguments to send-keys, capture-pane, split-window, join-pane where it
  makes sense to do so.

* Ignore named buffers when choosing a buffer if one is not specified by the user.

CHANGES FROM 3.3 TO 3.3a

* Do not crash when run-shell produces output from a config file.

* Do not unintentionally turn off all mouse mode when button mode is also
  present.

CHANGES FROM 3.2a TO 3.3

* Add an ACL list for users connecting to the tmux socket. Users may be
  forbidden from attaching, forced to attach read-only, or allowed to attach
  read-write. A new command, server-access, configures the list. File system
  permissions must still be configured manually.

* Emit window-layout-changed on swap-pane.

* Better error reporting when applying custom layouts.

* Handle ANSI escape sequences in run-shell output.

* Add pane_start_path to match start_command.

* Set PWD so shells have a hint about the real path.

* Do not allow pipe-pane on dead panes.

* Do not report mouse positions (incorrectly) above the maximum of 223 in
  normal mouse mode.

* Add an option (default off) to control the passthrough escape sequence.

* Support more mouse buttons when the terminal sends them.

* Add a window-resized hook which is fired when the window is actually resized
  which may be later than the client resize.

* Add next_session_id format with the next session ID.

* Add formats for client and server UID and user.

* Add argument to refresh-client -l to forward clipboard to a pane.

* Add remain-on-exit-format to set text shown when pane is dead.

* With split-window -f use percentages of window size not pane size.

* Add an option (fill-character) to set the character used for unused areas of
  a client.

* Add an option (scroll-on-clear) to control if tmux scrolls into history on
  clear.

* Add a capability for OSC 7 and use it similarly to how the title is set (and
  controlled by the same set-titles option).

* Add support for systemd socket activation (where systemd creates the Unix
  domain socket for tmux rather than tmux creating it). Build with
  --enable-systemd.

* Add an option (pane-border-indicators) to select how the active pane is shown
  on the pane border (colour, arrows or both).

* Support underscore styles with capture-pane -e.

* Make pane-border-format a pane option rather than window.

* Respond to OSC 4 queries

* Fix g/G keys in modes to do the same thing as copy mode (and vi).

* Bump the time terminals have to respond to device attributes queries to three
  seconds.

* If automatic-rename is off, allow the rename escape sequence to set an empty
  name.

* Trim menu item text more intelligently.

* Add cursor-style and cursor-colour options to set the default cursor style
  and colour.

* Accept some useful and non-conflicting emacs keys in vi normal mode at the
  command prompt.

* Add a format modifier (c) to force a colour to RGB.

* Add -s and -S to display-popup to set styles, -b to set lines and -T to set
  popup title. New popup-border-lines, popup-border-style and popup-style
  options set the defaults.

* Add -e flag to set an environment variable for a popup.

* Make send-keys without arguments send the key it is bound to (if bound to a
  key).

* Try to leave terminal cursor at the right position even when tmux is drawing
  its own cursor or selection (such as at the command prompt and in choose
  mode) for people using screen readers and similar which can make use of it.

* Change so that {} is converted to tmux commands immediately when parsed. This
  means it must contain valid tmux commands. For commands which expand %% and
  %%%, this now only happens within string arguments. Use of nested aliases
  inside {} is now forbidden. Processing of commands given in quotes remains
  the same.

* Disable evports on SunOS since they are broken.

* Do not expand the file given with tmux -f so it can contain :s.

* Bump FORMAT_LOOP_LIMIT and add a log message when hit.

* Add a terminal feature for the mouse (since FreeBSD termcap does not have kmous).

* Forbid empty session names.

* Improve error reporting when the tmux /tmp directory cannot be created or
  used.

* Give #() commands a one second grace period where the output is empty before
  telling the user they aren't doing anything ("not ready").

* When building, pick default-terminal from the first of tmux-256color, tmux,
  screen-256color, screen that is available on the build system (--with-TERM
  can override).

* Do not close popups on resize, instead adjust them to fit.

* Add a client-active hook.

* Make window-linked and window-unlinked window options.

* Do not configure on macOS without the user making a choice about utf8proc
  (either --enable-utf8proc or --disable-utf8proc).

* Do not freeze output in panes when a popup is open, let them continue to
  redraw.

* Add pipe variants of the line copy commands.

* Change copy-line and copy-end-of-line not to cancel and add -and-cancel
  variants, like the other copy commands.

* Support the OSC palette-setting sequences in popups.

* Add a pane-colours array option to specify the defaults palette.

* Add support for Unicode zero-width joiner.

* Make newline a style delimiter as well so they can cross multiple lines for
  readability in configuration files.

* Change focus to be driven by events rather than scanning panes so the
  ordering of in and out is consistent.

* Add display-popup -B to open a popup without a border.

* Add a menu for popups that can be opened with button three outside the popup
  or on the left or top border. Resizing now only works on the right and bottom
  borders or when using Meta. The menu allows a popup to be closed, expanded to
  the full size of the client, centered in the client or changed into a pane.

* Make command-prompt and confirm-before block by default (like run-shell). A
  new -b flags runs them in the background as before. Also set return code for
  confirm-before.

* Change cursor style handling so tmux understands which sequences contain
  blinking and sets the flag appropriately, means that it works whether cnorm
  disables blinking or not. This now matches xterm's behaviour.

* More accurate vi(1) word navigation in copy mode and on the status line. This
  changes the meaning of the word-separators option: setting it to the empty
  string is equivalent to the previous behavior.

* Add -F for command-prompt and use it to fix "Rename" on the window menu.

* Add different command histories for different types of prompts ("command",
  "search" etc).

CHANGES FROM 3.2 TO 3.2a

* Add an "always" value for the "extended-keys" option; if set then tmux will
  forward extended keys to applications even if they do not request them.

* Add a "mouse" terminal feature so tmux can enable the mouse on terminals
  where it is known to be supported even if terminfo(5) says otherwise.

* Do not expand the filename given to -f so it can contain colons.

* Fixes for problems with extended keys and modifiers, scroll region,
  source-file, cross compiling, format modifiers and other minor issues.

CHANGES FROM 3.1c TO 3.2

* Add a flag to disable keys to close a message.

* Permit shortcut keys in buffer, client, tree modes to be configured with a
  format (-K flag to choose-buffer, choose-client, choose-tree).

* Add a current_file format for the config file being parsed.

* When display-message used in config file, show the message after the config
  file finishes.

* Add client-detached notification in control mode.

* Improve performance of format evaluation.

* Make jump command support UTF-8 in copy mode.

* Support X11 colour names and other colour formats for OSC 10 and 11.

* Add "pipe" variants of "copy-pipe" commands which do not copy.

* Include "focused" in client flags.

* Send Unicode directional isolate characters around horizontal pane borders if
  the terminal supports UTF-8 and an extension terminfo(5) capability "Bidi" is
  present.

* Add a -S flag to new-window to make it select the existing window if one
  with the given name already exists rather than failing with an error.

* Add a format modifier to check if a window or session name exists (N/w or
  N/s).

* Add compat clock_gettime for older macOS.

* Add a no-detached choice to detach-on-destroy which detaches only if there
  are no other detached sessions to switch to.

* Add rectangle-on and rectangle-off copy mode commands.

* Change so that window_flags escapes # automatically. A new format
  window_raw_flags contains the old unescaped version.

* Add -N flag to never start server even if command would normally do so.

* With incremental search, start empty and only repeat the previous search if
  the user tries to search again with an empty prompt.

* Add a value for remain-on-exit that only keeps the pane if the program
  failed.

* Add a -C flag to run-shell to use a tmux command rather than a shell command.

* Do not list user options with show-hooks.

* Remove current match indicator in copy mode which can't work anymore since we
  only search the visible region.

* Make synchronize-panes a pane option and add -U flag to set-option to unset
  an option on all panes.

* Make replacement of ##s consistent when drawing formats, whether followed by
  [ or not. Add a flag (e) to the q: format modifier to double up #s.

* Add -N flag to display-panes to ignore keys.

* Change how escaping is processed for formats so that ## and # can be used in
  styles.

* Add a 'w' format modifier for string width.

* Add support for Haiku.

* Expand menu and popup -x and -y as formats.

* Add numeric comparisons for formats.

* Fire focus events even when the pane is in a mode.

* Add -O flag to display-menu to not automatically close when all mouse buttons
  are released.

* Allow fnmatch(3) wildcards in update-environment.

* Disable nested job expansion so that the result of #() is not expanded again.

* Use the setal capability as well as (tmux's) Setulc.

* Add -q flag to unbind-key to hide errors.

* Allow -N without a command to change or add a note to an existing key.

* Add a -w flag to set- and load-buffer to send to clipboard using OSC 52.

* Add -F to set-environment and source-file.

* Allow colour to be spelt as color in various places.

* Add n: modifier to get length of a format.

* Respond to OSC colour requests if a colour is available.

* Add a -d option to display-message to set delay.

* Add a way for control mode clients to subscribe to a format and be notified
  of changes rather than having to poll.

* Add some formats for search in copy mode (search_present, search_match).

* Do not wait on shutdown for commands started with run -b.

* Add -b flags to insert a window before (like the existing -a for after) to
  break-pane, move-window, new-window.

* Make paste -p the default for ].

* Add support for pausing a pane when the output buffered for a control mode
  client gets too far behind. The pause-after flag with a time is set on the
  pane with refresh-client -f and a paused pane may be resumed with
  refresh-client -A.

* Allow strings in configuration files to span multiple lines - newlines and
  any leading whitespace are removed, as well as any following comments that
  couldn't be part of a format. This allows long formats or other strings to be
  annotated and indented.

* Instead of using a custom parse function to process {} in configuration
  files, treat as a set of statements the same as outside {} and convert back
  to a string as the last step. This means the rules are consistent inside and
  outside {}, %if and friends work at the right time, and the final result
  isn't littered with unnecessary newlines.

* Add support for extended keys - both xterm(1)'s CSI 27 ~ sequence and the
  libtickit CSI u sequence are accepted; only the latter is output. tmux will
  only attempt to use these if the extended-keys option is on and it can detect
  that the terminal outside supports them (or is told it does with the
  "extkeys" terminal feature).

* Add an option to set the pane border lines style from a choice of single
  lines (ACS or UTF-8), double or heavy (UTF-8), simple (plain ASCII) or number
  (the pane numbers). Lines that won't work on a non-UTF-8 terminal are
  translated back into ACS when they are output.

* Make focus events update the latest client (like a key press).

* Store UTF-8 characters differently to reduce memory use.

* Fix break-pane -n when only one pane in the window.

* Instead of sending all data to control mode clients as fast as possible, add
  a limit of how much data will be sent to the client and try to use it for
  panes with some degree of fairness.

* Add an active-pane client flag (set with attach-session -f, new-session -f
  or refresh-client -f). This allows a client to have an independent active
  pane for interactive use (the window client pane is still used for many
  things however).

* Add a mark to copy mode, this is set with the set-mark command (bound to X)
  and appears with the entire line shown using copy-mode-mark-style and the
  marked character in reverse. The jump-to-mark command (bound to M-x) swaps
  the mark and the cursor positions.

* Add a -D flag to make the tmux server run in the foreground and not as a
  daemon.

* Do not loop forever in copy mode when search finds an empty match.

* Fix the next-matching-bracket logic when using vi(1) keys.

* Add a customize mode where options may be browsed and changed, includes
  adding a brief description of each option. Bound to C-b C by default.

* Change message log (C-b ~) so there is one for the server rather than one per
  client and it remains after detach, and make it useful by logging every
  command.

* Add M-+ and M-- to tree mode to expand and collapse all.

* Change the existing client flags for control mode to apply for any client,
  use the same mechanism for the read-only flag and add an ignore-size flag.

  refresh-client -F has become -f (-F stays for backwards compatibility) and
  attach-session and switch-client now have -f flags also. A new format
  client_flags lists the flags and is shown by list-clients by default.

  This separates the read-only flag from "ignore size" behaviour (new
  ignore-size) flag - both behaviours are useful in different circumstances.

  attach -r and switchc -r remain and set or toggle both flags together.

* Store and restore cursor position when copy mode is resized.

* Export TERM_PROGRAM and TERM_PROGRAM_VERSION like various other terminals.

* Add formats for after hook command arguments: hook_arguments with all the
  arguments together; hook_argument_0, hook_argument_1 and so on with
  individual arguments; hook_flag_X if flag -X is present; hook_flag_X_0,
  hook_flag_X_1 and so on if -X appears multiple times.

* Try to search the entire history first for up to 200 ms so a search count can
  be shown. If it takes too long, search the visible text only.

* Use VIS_CSTYLE for paste buffers also (show \012 as \n).

* Change default formats for tree mode, client mode and buffer mode to be more
  compact and remove some clutter.

* Add a key (e) in buffer mode to open the buffer in an editor. The buffer
  contents is updated when the editor exits.

* Add -e flag for new-session to set environment variables, like the same flag
  for new-window.

* Improve search match marking in copy mode. Two new options
  copy-mode-match-style and copy-mode-current-match-style to set the style for
  matches and for the current match respectively. Also a change so that if a
  copy key is pressed with no selection, the current match (if any) is copied.

* Sanitize session names like window names instead of forbidding invalid ones.

* Check if the clear terminfo(5) capability starts with CSI and if so then
  assume the terminal is VT100-like, rather than relying on the XT capability.

* Improve command prompt tab completion and add menus both for strings and -t
  and -s (when used without a trailing space). command-prompt has additional
  flags for only completing a window (-W) and a target (-T), allowing C-b ' to
  only show windows and C-b . only targets.

* Change all the style options to string options so they can support formats.
  Change pane-active-border-style to use this to change the border colour when
  in a mode or with synchronize-panes on. This also implies a few minor changes
  to existing behaviour:

  - set-option -a with a style option automatically inserts a comma between the
    old value and appended text.

  - OSC 10 and 11 no longer set the window-style option, instead they store the
    colour internally in the pane data and it is used as the default when the
    option is evaluated.

  - status-fg and -bg now override status-style instead of the option values
    being changed.

* Add extension terminfo(5) capabilities for margins and focus reporting.

* Try $XDG_CONFIG_HOME/tmux/tmux.conf as well as ~/.config/tmux/tmux.conf for
  configuration file (the search paths are in TMUX_CONF in Makefile.am).

* Remove the DSR 1337 iTerm2 extension and replace by the extended device
  attributes sequence (CSI > q) supported by more terminals.

* Add a -s flag to copy-mode to specify a different pane for the source
  content. This means it is possible to view two places in a pane's history at
  the same time in different panes, or view the history while still using the
  pane. Pressing r refreshes the content from the source pane.

* Add an argument to list-commands to show only a single command.

* Change copy mode to make copy of the pane history so it does not need to
  freeze the pane.

* Restore pane_current_path format from portable tmux on OpenBSD.

* Wait until the initial command sequence is done before sending a device
  attributes request and other bits that prompt a reply from the terminal. This
  means that stray replies are not left on the terminal if the command has
  attached and then immediately detached and tmux will not be around to receive
  them.

* Add a -f filter argument to the list commands like choose-tree.

* Move specific hooks for panes to pane options and windows for window options
  rather than all hooks being session options. These hooks are now window options:

  window-layout-changed
  window-linked
  window-pane-changed
  window-renamed
  window-unlinked

  And these are now pane options:

  pane-died
  pane-exited
  pane-focus-in
  pane-focus-out
  pane-mode-changed
  pane-set-clipboard

  Any existing configurations using these hooks on a session rather than
  globally (that is, set-hook or set-option without -g) may need to be changed.

* Show signal names when a process exits with remain-on-exit on platforms which
  have a way to get them.

* Start menu with top item selected if no mouse and use mode-style for the
  selected item.

* Add a copy-command option and change copy-pipe and friends to pipe to it if
  used without arguments, allows all the default copy key bindings to be
  changed to pipe with one option rather than needing to change each key
  binding individually.

* Tidy up the terminal detection and feature code and add named sets of
  terminal features, each of which are defined in one place and map to a
  builtin set of terminfo(5) capabilities. Features can be specified based on
  TERM with a new terminal-features option or with the -T flag when running
  tmux. tmux will also detect a few common terminals from the DA and DSR
  responses.

  This is intended to make it easier to configure tmux's use of terminfo(5)
  even in the presence of outdated ncurses(3) or terminfo(5) databases or for
  features which do not yet have a terminfo(5) entry. Instead of having to grok
  terminfo(5) capability names and what they should be set to in the
  terminal-overrides option, the user can hopefully just give tmux a feature
  name and let it do the right thing.

  The terminal-overrides option remains both for backwards compatibility and to
  allow tweaks of individual capabilities.

* Support mintty's application escape sequence (means tmux doesn't have to
  delay to wait for Escape, so no need to reduce escape-time when using
  mintty).

* Change so main-pane-width and height can be given as a percentage.

* Support for the iTerm2 synchronized updates feature (allows the terminal to
  avoid unnecessary drawing while output is still in progress).

* Make the mouse_word and mouse_line formats work in copy mode and enable the
  default pane menu in copy mode.

* Add a -T flag to resize-pane to trim lines below the cursor, moving lines out
  of the history.

* Add a way to mark environment variables as "hidden" so they can be used by
  tmux (for example in formats) but are not set in the environment for new
  panes. set-environment and show-environment have a new -h flag and there is a
  new %hidden statement for the configuration file.

* Change default position for display-menu -x and -y to centre rather than top
  left.

* Add support for per-client transient popups, similar to menus but which are
  connected to an external command (like a pane). These are created with new
  command display-popup.

* Change double and triple click bindings so that only one is fired (previously
  double click was fired on the way to triple click). Also add default double
  and triple click bindings to copy the word or line under the cursor and
  change the existing bindings in copy mode to do the same.

* Add a default binding for button 2 to paste.

* Add -d flag to run-shell to delay before running the command and allow it to
  be used without a command so it just delays.

* Add C-g to cancel command prompt with vi keys as well as emacs, and q in
  command mode.

* When the server socket is given with -S, create it with umask 177 instead of
